Don't know how feasible this would be, but it would be nice to mark cards in collections as "Used by X Deck" so that they aren't counted as owned for other decks when you use the same cards across multiple decks. Really enjoy being able to use the databases to keep track of what I do or don't have at a glance so I know what needs to be ordered. Sometimes there is overlap and I think I own something but its in use in another deck and I need another copy. Would just be a nice QoL thing if its in the cards.